This invention relates to fluidized bed reactor systems and to the production of polycrystalline silicon from a thermally decomposable silicon compound such as, for example, silane.
Fluidized bed reactors are used to carry out multiphase reactions. In typical fluidized bed reactor systems a fluid is passed through a bed of granular material such as a catalyst or growing product particles. The flow of fluid causes the bed of granular material to become fluidized in the reactor.
In many fluidized bed reactor systems and especially in systems where material from the fluid phase chemically decomposes to form solid material, solids may deposit onto the walls of the reactor. The wall deposits often alter the reactor geometry which can decrease reactor performance. Further, portions of the wall deposits can dislodge from the reactor wall and fall to the reactor bottom. Often the reactor system must be shut down to remove the dislodged deposits. To prevent an untimely reactor shut down, the deposits must be periodically etched from the reactor wall and the reactor must be cleaned thereby reducing the productivity of the reactor. These problems are particularly acute in fluidized bed reactor systems used in the production of polycrystalline silicon.
Thus a need exists for reactor systems and methods for producing polycrystalline silicon which limit or reduce the amount of deposits that form on the reactor walls.